An extensive discussion of the background, development, features and application of an operating embodiment of the invention is described and illustrated in SAE Paper No. 831744 entitled "Development of Detroit Diesel Allison 6-V92TA Methanol Fueled Coach Engine" by R. R. Toepel, J. E. Bennethum, and R. E. Heruth, published in conjunction with the fuels and lubricants Meeting at San Francisco, Calif., on Oct. 31-Nov. 3, 1983. Reference to this paper is recommended for its detailed discussion of the subject matter subsequently described herein and the disclosure of this paper is hereby incorporated herein by reference.
In its broader aspects the invention provides a method of operation and means for operating two-stroke cycle (two-cycle) blower scavenged diesel engines on direct injected liquid methanol fuels, or other fuels of low ignition quality (low cetane), such as ethanol and similar alcohols.
In a specific embodiment the invention provides bypass blower means for controlling scavenging of the cylinders of a turbocharged two-cycle blower scavenged diesel engine to maintain charge temperatures high enough for compression ignition of injected methanol fuel by using the heat of exhaust residuals retained from the previous cycle to the extent required under varying operating conditions.
Other features of the invention include the provision of cylinder head mounted glow plugs for aiding ignition of direct injected methanol during starting; selection of a slightly increased piston compression ratio and slightly reduced blower drive speed together with a reduced flow turbocharger, as compared with the comparable diesel engine, for matching engine air system requirements; increased flow capacity injectors to provide the additional fuel rate required and a bypass blower air control system for maintaining the required charge temperatures.
These and other features of the invention will be more fully understood from the following description of a specific embodiment taken together with the accompanying drawings.